Traveling grate for stokers



Aug. 22, 1944. R. BEERS TRAVELING GRATE FOR STOKERS Filed March 9, 1942 2 Sheets-Sheet 1 m m D M N E VE N m m IF m T T E 5 E A G l G Y n E m 0 m K F R M Aug. 22, 1944. R. L. BEERS TRAVELING GRATE FOR STOKERS 2 Sheets- Sheet 2 Filed March 9, 1942 j no.2.

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ROYCE L.BEERS ATTORNEYV Patented Aug. 22, 1944 TRAVELING GRATE FOR STOKERS Royce L. Beers, Birmingham, Mich., assignor to Detroit Stoker Company, Monroe, Mich., a corporation of Michigan Application March 9, 1942, Serial No. 433,979

6 Claims.

The invention relates to traveling grates of that type in which individual transversely extending grate bars are pivotally connected to propelling sprocket chains which pass around forward and rear sprockets. The fuel during the combustion thereof is supported on a horizontally extending portion of the grate while the ash is carried around the sprockets at one end and deposited in the ash pit. To prevent the sifting of fuel between adjacent bars, each has a portion overlapping a ledge on the succeeding bar, said ledge being of an arcuate contour so as to main tain the seal while the bars are passing around the sprocket. Inasmuch, however, as the bars are pivotally attached to the sprocket chains beneath their forward edge portions, they are free to turn on these pivots and might therefore separate from each other when descending over the sprocket. Such separation has heretofore been prevented by providing arcuate guide rails at opposite ends of the grate bars which are concentric with the sprockets and hold the bars thereagainst while traveling therearound.

In the commercial manufacture of traveling grates of this type, it has been found difiicult to maintain all of the grate bars of exactly uniform thickness, and if the guide rails are adjusted to permit passage of the rails of maximum thickness, they will not contact with the thinner bars. This will permit sufficient relative movement to open a gap between adjacent bars and permit the sifting of the fuel or ash therebetween.

It is the object of the instant invention to obtain a construction which will hold the bars against separation while passing about the sprockets and which is independent of variation in thickness of said bars. To this end the invention consists in the construction as hereinafter set forth.

In the drawings:

Fig. 1 is a side elevation of a portion of my improved grate;

Fig. 2 is a section on line 2--2 of Fig. 1;

Fig. 3 is an end elevation of one of the flexible shoes;

Fig. 4 is a similar view of another of the shoes; and

Fig. 5 is a side elevation similar to a portion of Figure 1, showing a slightly modified construction.

The chain grate to which my improvements are applied comprises parallelly arranged transversely extending grate bars A in one or more parallel series, sprocket chains B, B, to which said bars are pivotally connected, and sprockets 0 around which the chains and bars pass. Each grate bar has adjacent to its forward edge a depending flange D and forwardly extending lugs E apertured for the passage of the pivot pins F which connect the bar to the chain. Above the lugs E, but beneath the top of the bar is the segmental ledge G, which is concentric with the pivot F. This ledge supports the rear edge of the forward adjacent bar which is thus held in sealing contact therewith by the weight of the fuel or ash carried by the grate. The pivot pin F is also the pivotal connection between links H of the sprocket chain, and consequently, when this chain passes around a sprocket, there will be a relative separating movement between the outer portions of adjacent grate bars. This will not, however, open up any gap through which the fuel or ash can pass, as the ledge G maintains the seal.

To carry the load on the portion of the grate which supports the fuel bed, there is arranged beneath the opposite end portions of the bars A supporting rails I. These extend horizontally between the sprockets C, and where the grate is formed of a plurality of sections, a single rail I will support the ends of adjacent sections. Thus the propelling chains formed by the links H are relieved from the load on the bars until they come into engagement with the sprockets.

As heretofore described, the grate bars, when descending around the sprockets C, are free to independently turn on their pivots F and, if not restrained would fall away from each other. However, restraining guide rails have heretofore been arranged to engage opposite ends of the bars and to hold them in contact with each other while traveling around the sprocket, provided all of the bars are of uniform thickness. If, on the other hand, the bars vary in thickness, then the thinner bars would still be free to separate sufiiciently from the ledge of the following bar to permit the passage of fuel or ash.

To cur'e this defect, I have substituted for the rigid guide, as heretofore used, resilient yieldable means for pressing the individual bars against each other when traveling around the sprocket. As specifically shown, this means is of the following construction:

J is a guide rail section or shoe, adjacent to the end of the horizontal run of the chain grate and having an arcuate portion concentric with the sprocket. This rail is of a T-shaped cross section, one of the flanges J thereof overlapping the ends of the grate bars while the opposite flange overlaps a filler J Where the grate is formed of a plurality of sections, guide rails J are arranged between adjacent sections, and both the flanges J thereof will contact with the ends of grate bars. The rail J is yieldably held in position by bolts K and K at opposite ends thereof, which extend inward and have sleeved thereon coil springs K The inner end of each spring engages a collar K on the bolt, while its outer end engages a suitable stationary abutment. The normal position of the rail is such as to contact with a grate bar of minimum thickness, and Where thicker bars travel along the rail, it will move outward against the tension of the springs K Connected to the outer end of the shoe J is a flexible chain or shoe, preferably formed of a series of links L pivotally connected to each other. These links are yieldably pressed against the individual grate bars, preferably by a toggle lever M having one member M thereof pivotally connected to the upper link and the other member M pivotally connected to the lowermost link. These two members are pivotally connected to each other at M and a counterweight N is supported therefrom. This provides sufficient radially inwardly directed pressure on the links to hold the grate bars from separating while at the same time yielding to permit passage of thicker bars. In place of the counterweight N any other suitable tensioning means may be substituted, such as the spring N Fig. 5.

The construction just described and as illustrated in Fig. 3 is applied to the opposite ends of each series of grate bars, and where there is more than one series, the modified construction as. shown in Fig. 4 is applied between series. This has two parallel series of links L and toggle levers M and a single counterweight N connected by a yoke O to both series.

The outer face of each grate bar is convex and forms an arc of a radius corresponding to that of the sprocket. Also, the links L are formed with concave faces of substantially the same radius, so that they will fit against the individual grate bars. If the faces of the links in contact with the bars become worn after continued use, the links may be reversed so as to bring the opposite faces thereof in bearing contact with the bars.

What I claim as my invention is:

l. A traveling grate comprising a propelling chain, a sprocket around which said chain passes, a series of grate bars each pivotally connected at one edge to said chain and having its opposite edge forming closed slidable contact with an arcuate surface on an adjacent bar concentric with the pivotal connection thereof, and resilient means for holding said bars in sliding contact with each other while passing around said sprocket.

2. A traveling grate comprising a propelling chain, a sprocket around which said chain passes, a series of grate bars each pivotally connected at one edge to said chain and having its opposite edge forming closed slidable contact with an arcuate surface on an adjacent bar concentric With the pivotal connection thereof, and a flexible shoe, yieldably bearing against said bars while passing around said sprocket to maintain closed contact between bars.

3. A traveling grate comprising a propelling chain, a sprocket around which said chain passes, a series of grate bars each pivotally connected at one edge to said chain and having its opposite edge forming closed contact with an adjacent bar, and means for holding said bars in contact with each other while passing around said sprocket comprising a series of pivotally connected links wrapped about the bars engaging the sprocket, and tensioning means for yieldably pressing said links against the individual bars.

4. A traveling grate comprising a propelling chain, a sprocket around which said chain passes, a series of grate bars each pivotally connected at one edge to said chain and having its opposite edge forming closed contact with an adjacent bar, and means for holding said bars in closed contact with each other while passing about said sprocket comprising a segmental shoe extending over a segment of the sprocket, a chain connected to said shoe formed of a series of links corresponding to the individual grate bars and wrapped about another segment of the sprocket, and tensioning means for yieldably holding said shoe and chain in contact with said bars.

5. A traveling grate comprising a propelling chain, a sprocket around which said chain passes, a series of grate bars each pivotally connected at one edge to said chain and having its opposite edge forming closed contact with an adjacent bar, and means for holding said bars in closed contact with each other while passing around said sprocket comprising a flexible shoe including a series of pivotally connected links, a toggle lever connected to the end links of the series, and a tensioning means connected to said toggle lever, whereby said shoe is yieldably pressed against said grate bars. I

6. A traveling grate comprising a propelling chain, a sprocket around which said chain passes, a series of grate bars having convex outer faces each pivotally connected at one edge to said chain and having its opposite edge forming closed contact with an adjacent bar, and means for holding said bars in closed contact with each other while passing around said sprocket comprising a flexible shoe including a series of pivotally connected links wrapped about said bars, said links having opposite concave segmental faces corresponding in radius to the convex faces on said bars and being reversible, and tensioning means for yieldably holding said links in contact with said bars.

ROYCE L. BEERS. 

